Data from: Rapid adaptive evolution in novel environments acts as an architect of population range expansion

Colonization and expansion into novel landscapes determine the distribution and abundance of species in our rapidly changing ecosystems worldwide. Colonization events are crucibles for rapid evolution, but it is not known whether evolutionary changes arise mainly after successful colonization has occurred, or if evolution plays an immediate role, governing the growth and expansion speed of colonizing populations. There is evidence that spatial evolutionary processes can speed range expansion within a few generations because dispersal tendencies may evolve upwards at range edges. Additionally, rapid adaptation to a novel environment can increase population growth rates, which also promotes spread. However, the role of adaptive evolution and the relative contributions of spatial evolution and adaptation to expansion are unclear. Using a model system, red flour beetles (Tribolium castaneum), we either allowed or constrained evolution of populations colonizing a novel environment, and measured population growth and spread. At the end of the experiment we assessed the fitness and dispersal tendency of individuals originating either from the core or edge of evolving populations or from nonevolving populations in a common garden. Within six generations, evolving populations grew three times larger and spread 46% faster than populations in which evolution was constrained. Increased size and expansion speed were strongly driven by adaptation, whereas spatial evolutionary processes acting on edge subpopulations contributed minimally. This experimental evidence demonstrates that rapid evolution drives both population growth and expansion speed, and is thus crucial to consider for managing biological invasions and successfully introducing or reintroducing species for management and conservation.在全球快速变化的生态系统中，物种的分布与种群丰度由其对新异生境的定殖与扩张过程决定。定殖事件是快速演化的天然熔炉，但目前学界仍不清楚：演化改变主要发生在成功定殖之后，还是演化会即刻发挥作用，调控定殖种群的生长与扩张速率。已有研究证实，空间演化过程可在数代之内加速物种分布范围扩张——这是由于种群分布边界处的扩散倾向会向上演化（即扩散能力增强）。此外，对新异环境的快速适应性演化可提升种群生长速率，同样能促进种群扩散。然而，适应性演化的具体作用，以及空间演化与适应性演化对种群扩张的相对贡献，目前仍不明确。本研究以模式生物红粉甲虫（赤拟谷盗，*Tribolium castaneum*）为实验系统，分别设置允许演化与限制演化两组处理，对定殖于新异环境的种群展开实验，并测定其种群生长与扩散情况。实验结束后，我们在同质园（common garden）环境中，对来自演化种群核心区、边界区以及非演化种群的个体的适合度与扩散倾向进行了评估。仅历经六代，允许演化的种群规模较演化受限的种群扩大至3倍，扩张速率提升46%。种群规模与扩张速率的提升主要由适应性演化驱动，而作用于边界亚种群的空间演化过程贡献极小。本实验证据表明，快速演化同时调控种群生长与扩张速率，因此在生物入侵管理，以及为保护与管理目标成功引入或再引入物种的实践中，必须将演化因素纳入考量范畴。